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Diffstat (limited to 'vendor/lukechampine.com/uint128/README.md')
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diff --git a/vendor/lukechampine.com/uint128/README.md b/vendor/lukechampine.com/uint128/README.md new file mode 100644 index 00000000..1ea5d7df --- /dev/null +++ b/vendor/lukechampine.com/uint128/README.md @@ -0,0 +1,46 @@ +uint128 +------- + +[](https://godoc.org/github.com/lukechampine/uint128) +[](https://goreportcard.com/report/github.com/lukechampine/uint128) + +``` +go get lukechampine.com/uint128 +``` + +`uint128` provides a high-performance `Uint128` type that supports standard arithmetic +operations. Unlike `math/big`, operations on `Uint128` values always produce new values +instead of modifying a pointer receiver. A `Uint128` value is therefore immutable, just +like `uint64` and friends. + +The name `uint128.Uint128` stutters, so I recommend either using a "dot import" +or aliasing `uint128.Uint128` to give it a project-specific name. Embedding the type +is not recommended, because methods will still return `uint128.Uint128`; this means that, +if you want to extend the type with new methods, your best bet is probably to copy the +source code wholesale and rename the identifier. ¯\\\_(ツ)\_/¯ + + +# Benchmarks + +Addition, multiplication, and subtraction are on par with their native 64-bit +equivalents. Division is slower: ~20x slower when dividing a `Uint128` by a +`uint64`, and ~100x slower when dividing by a `Uint128`. However, division is +still faster than with `big.Int` (for the same operands), especially when +dividing by a `uint64`. + +``` +BenchmarkArithmetic/Add-4 2000000000 0.45 ns/op 0 B/op 0 allocs/op +BenchmarkArithmetic/Sub-4 2000000000 0.67 ns/op 0 B/op 0 allocs/op +BenchmarkArithmetic/Mul-4 2000000000 0.42 ns/op 0 B/op 0 allocs/op +BenchmarkArithmetic/Lsh-4 2000000000 1.06 ns/op 0 B/op 0 allocs/op +BenchmarkArithmetic/Rsh-4 2000000000 1.06 ns/op 0 B/op 0 allocs/op + +BenchmarkDivision/native_64/64-4 2000000000 0.39 ns/op 0 B/op 0 allocs/op +BenchmarkDivision/Div_128/64-4 2000000000 6.28 ns/op 0 B/op 0 allocs/op +BenchmarkDivision/Div_128/128-4 30000000 45.2 ns/op 0 B/op 0 allocs/op +BenchmarkDivision/big.Int_128/64-4 20000000 98.2 ns/op 8 B/op 1 allocs/op +BenchmarkDivision/big.Int_128/128-4 30000000 53.4 ns/op 48 B/op 1 allocs/op + +BenchmarkString/Uint128-4 10000000 173 ns/op 48 B/op 1 allocs/op +BenchmarkString/big.Int-4 5000000 350 ns/op 144 B/op 3 allocs/op +``` |